Alternative method of diffraction-enhanced imaging

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Abstract

Diffraction-enhanced imaging (DEI) is a radiographic technique that derives contrast from an object's X-ray absorption, refraction gradient and small-angle scatter properties (extinction). The DEI imaging system prepares the incident beam by diffraction from highly perfect crystals and then subsequently analyzes the beam transmitted through the object being imaged with another crystal. To apply DEI, two images are acquired with the analyzer crystal set on each side of the rocking curve. The low-angle side and the high-angle side images were combined to obtain refraction angle and apparent absorption images. An alternative method of obtaining those images of the object is presented in which the analyzer is fixed and the object is rotated. The resultant images verify the new analysis method and are compared with the images obtained by the original method of DEI. This method may be useful in situations where it is important to keep the analyzer fixed in angle which may improve the angular stability of the system.